std: remove the equals method from TotalEq.

`TotalEq` is now just an assertion about the `Eq` impl of a
type (i.e. `==` is a total equality if a type implements `TotalEq`) so
the extra method is just confusing.

Also, a new method magically appeared as a hack to allow deriving to
assert that the contents of a struct/enum are also TotalEq, because the
deriving infrastructure makes it very hard to do anything but create a
trait method. (You didn't hear about this horrible work-around from me
:(.)

src/libstd/vec.rs

@@ -339,12 +339,7 @@ impl<T: Ord> Ord for Vec<T> {
     }
 }
 
-impl<T: TotalEq> TotalEq for Vec<T> {
-    #[inline]
-    fn equals(&self, other: &Vec<T>) -> bool {
-        self.as_slice().equals(&other.as_slice())
-    }
-}
+impl<T: TotalEq> TotalEq for Vec<T> {}
 
 impl<T: TotalOrd> TotalOrd for Vec<T> {
     #[inline]